1. Field
The present invention relates to wireless data communication. More particularly, the present invention relates to a novel and improved method and apparatus for scheduling packet data transmissions in a wireless communication system.
2. Background
In a wireless communication system, a base station communicates with multiple mobile users. Wireless communications may include low delay data communications, such as voice or video transmissions, or high data rate communications, such as packetized data transmissions. U.S. patent application Ser. No. 08/963,386, entitled xe2x80x9cMETHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,xe2x80x9d filed Nov. 3, 1997 describes high rate packet data transmissions, and is hereby expressly incorporated by reference.
Packet data transmissions are not required to be real-time transmissions, and therefore allow the base station flexibility in scheduling mobile user transmissions within a system. Once scheduled, the base station may transmit data to as little as a single mobile user during a given time period. In general, scheduling of packet data mobile users in a system has two goals. For example, channel quality conditions and the amount of pending data for a given user may result in excessive time allocations to that user. There is a need, therefore, for a fair method for scheduling efficient packet data transmissions to mobile users.
In one aspect, in a wireless communication system adapted for packet data transmissions, a method includes receiving a data rate request (DRR) indicator for a mobile station, determining a fairness parameter xcex1 for the mobile station, calculating a projected throughput value Txe2x80x2 for the mobile station as a function of the rate request indicator, calculating a priority function for the mobile station, wherein the priority function is a function of DRR/(Txe2x80x2)xcex1, and scheduling transmissions to the mobile stations according to the priority functions.
According to one aspect, a method for scheduling packet data transactions in a wireless communication system includes determining a pool of users, calculating a priority function of at least a portion of the pool of users, scheduling a first set of users having pending data transactions from the portion of the pool of users, receiving rate request indicators from the portion of the pool of users, and updating priority functions of the first set of users as the rate request indicators divided by a function of projected throughput and a fairness parameter.
In another aspect, a base station apparatus includes a processor, and a memory storage device coupled to the processor, the memory storage device operative to store a plurality of computer readable instructions. The memory storage device includes a first set of instructions to receive a rate request indicator DRR for a mobile station, a second set of instructions to determine a fairness parameter xcex1 for the mobile station, a third set of instructions to calculate a projected throughput value Txe2x80x2 for the mobile station as a function of the rate request indicator, a fourth set of instructions to calculate a priority function for the mobile station, wherein the priority function is a function of DRR/(Txe2x80x2)xcex1, and a fifth set of instructions to schedule transmissions to the mobile stations according to the priority functions.